Liquid crystal displays have characteristics of small volume, low power consumption, low radiation and so on, and thus have played a leading role in the market for flat panel displays at present. In the technical field of liquid crystal display, Thin film transistor liquid crystal displays (TFT-LCDs) have been widely applied to televisions, computers, mobile phones and other fields with the advantages of high integration, various functions, flexible process, low cost, etc.
A TFT-LCD is usually formed in such a way that an array substrate and a color filter substrate that have been manufacture are assembled together by cell-aligning and liquid crystals are filled therebetween, and it generally adopts a row-column matrix driving mode. As illustrated in FIG. 1, thin film transistors within sub-pixel regions in each row are charged sequentially by scan lines (also referred to as gate lines) and data lines disposed on the array substrate, so as to present colors; each of the sub-pixel regions comprises one thin film transistor, the gate electrodes of thin film transistors in sub-pixel regions in each of rows are connected to the same scan line, the source electrodes of them are connected to different data lines, and one scan line is disposed between every two adjacent rows of sub-pixel regions. In FIG. 1, “Gan” represents the nth scan line, “Drn” represents the nth data line, n is a positive integer greater than 1, M represents a thin film transistor, and M11 represents a thin film transistor that is connected to the first scan line and the first data line, respectively.
Among various parameters of the TFT-LCD, aperture ratio is an important factor that affects the screen brightness and power consumption. Aperture ratio refers to the ratio of the area of a portion that allows light to pass through in each sub-pixel region except the wirings and the thin film transistor to the overall area of the sub-pixel region. The higher the aperture ratio is, the higher the light transmittance is, and on the condition of the same backlight source, the brightness of the screen will become higher. Because the power consumption of a backlight source in a TFT-LCD takes up 60% or so of the overall power output, increasing of the aperture ratio can reduce power consumption of the backlight source on the premise of satisfying the screen brightness. Thereby, power consumption of the whole TFT-LCD is reduced. Therefore, how to increase the aperture ratio further more in the case of process conditions permitting becomes an urgent issue to be solved in the industry.